Proto-oncogenes and tumor-suppressor genes provide the __________ and inhibitory signals, respectively, that regulate the cell cycle

Stimulatory

___________________ is an enzyme that synthesizes sequences of telomeres, thereby enabling cells to proliferate endlessly

Telomerase

_________ and ___________are normal mechanisms for cell death. When the normal regulatory mechanisms for cellular growth fail, backup defense systems may be activated. These are secondary defenses and kick in when Primary defences such as EGFR/HER, Tumor supressor genes
and DNA repaid genes.

(1) Apoptosis (programmed cell death or suicide)

(2) Cellular senescence (aging)

(1) Cell-cycle phase-specific agents are generally given more frequently as ______________
(2) Whereas cell cycle phase-nonspecific agents are given as ____________